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  <title>Document</title>
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  <script>
    // 变量
    // let name = 'Jack'
    // let age = 18

    // name = 'Bit'
    // age = 20

    // 常量
    // const PI = 3.14
    // // PI = 3.1415926
    // const articleList = []
    // const user = {
    //   name: 'vue3',
    //   age: 9
    // }


    // 思考
    const arr = [1, 2, 3]
    // 添加
    arr.push(4)
    console.log(arr)
    // 删除
    arr.shift()
    console.log(arr)

    const obj = {
      name: 'vue3',
      age: 9
    }
    // 添加属性
    obj.birth = 2015
    console.log(obj)

    // 修改属性
    obj.age = 10
    console.log(obj)



  </script>
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